SKY & TELESCOPE'S NEWS BULLETIN -- January 3, 1995

JUPITER's COOL NEW BELT

Thanks to last summer's comet impacts, Jupiter sports a new dark belt in its
southern hemisphere, the second-most obvious one on Jupiter after the South
Equatorial Belt. Astronomers report that the band looks *bright* at the
infrared wavelength of 1.7 microns. This means that debris ejected upward
remains suspended high in the atmosphere. Now a team of European astronomers
report that the band is significantly dimmer -- and thus cooler -- than its
surroundings in the thermal infrared at 7.8 and 7.9 microns. These wavelengths
are sensitive to the presence of methane in Jupiter's middle stratosphere. The
team suggests either that the stratosphere now contains gases like water,
ammonia, and hydrogen cyanide which efficiently radiate energy to space, or
that a high-altitude haze above the impact zone is reflecting enough sunlight
to keep the gases below relatively cool. Jupiter currently rises more than two
hours before the Sun, sitting above the horizon in the southeast to the lower-
left of brilliant Venus.

MOST DISTANT GALAXY

Astronomers at the University of California, Berkeley, have used the 10-meter
Keck Telescope on Mauna Kea to record the most distant galaxy yet. Designated
8C 1435+63, this system has a measured redshift, z, of 4.25. Large values of z
correspond to fast motion away from Earth and thus great distances, and this
galaxy is an estimated 15 billion light-years away. The previous record holder
had a redshift of 3.8, though some quasars have redshifts as high as 4.9. Led
by Hyron Spinrad, the team finds the new galaxy to be about 150,000 to 200,000
light-years across -- some five times the size of nearby M31, the Andromeda
Galaxy. They observed it during March and July last year.

TAILS OF COMET P/BORRELLY

S&T Contributing Editor John Bortle says Periodic Comet Borrelly is an unusual
and impressive object. The comet is now about magnitude 8.5, making it easy to
spot with modest telescopes or even good binoculars. But through a larger
telescope P/Borrelly displays *two* faint tails, pointing toward and away from
the Sun at position angles of 265 and 115 degrees. Bortle adds that P/Borrelly
hasn't sported an antitail since its apparition in 1918. The comet is now
drifting slowly across the western stars of Ursa Major. As 1995 begins you'll
find it just barely west of the 3.8-magnitude star Upsilon Ursae Majoris. Here
are upcoming positions for 0 hours Universal Time:

QUADRANTID METEORS

This year the Quadrantid meteor shower should peak at about 23:00 Universal
Time on January 3rd. This shower is known for its sharp peak, but despite
Moonless skies this year the peak occurs during daylight in North America.
Viewers in Eastern Asia stand to have the best seats for seeing the crescendo
in predawn darkness.

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